Cytokeratins in the detection of tumors

Cytokeratins (CKs, or following more recent nomenclature also simply called keratins) are intermediate filament?forming proteins that provide mechanical support and fulfill a variety of additional functions in epithelial cells. They are part of the cytoskeleton and the largest family of intermediate filament proteins. Two types of Cytokeratins are distinguished that form heterodimers, namely acidic type I (Cytokeratins 9-23) and basic type II (Cytokeratins 1-8).

The specific nature of these heterodimers serves to distinguish different epithelial cells, in which they are expressed, and has also become important in the classification of tumor cells besides other protein tumor markers. Mutations in most of them are now associated with specific tissue-fragility disorders, and antibodies to Cytokeratins are important markers of tissue differentiation.

Importantly, they are tools in diagnostic pathology, most importantly in the detection of tumors. Primary tumors and metastases of a given carcinoma share the same pattern of cytokeratins, that distinguishes them from other types of carcinomas, thereby allowing differentiation between the different tumors (Ref. 1-4).

For example, Mesotheliomas (a protective lining that covers most of the body's internal organs) and Adenocarcinomas (originating in glandular tissue) can be distinguished by detection of . Defects in lead to inherited skin disorders such as epidermolysis bullosa simplex (EBS) or Dowling-Deogs disease (DDD) (Ref. 5-7).

can be used as a tool in order to distinguish ovarian and gastrointestinal carcinomas, or transitional cell carcinomas and prostate . In hepatocytes atypical expression of is a marker for primary biliary cirrhosis (Ref. 8-10).

and have a structural role in simple epithelia. Additionally, they play a role in signaling that modulates cell attachment, protein synthesis, G1/S phase transition, and in stress adaptation. Furthermore, can be applied to detect therapy-induced tumor apoptosis and necrosis (Ref. 11-14).

Squamous cell (that have protective functions to nutrition exchange) carcinomas can be diagnosed utilizing , and as biomarkers.

Because is being speculated to be linked to the retention of an undifferentiated cell character it may be useful in the detection of a variety of tumors (Ref 18-22).

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